Certain optical and electrical-optical devices have photonic integrated circuit boards (PICBs) that need to be optically interfaced (optically coupled) with another optical device so that optical signals can be received and processed by the device, and also transmitted from the device to another device or to a back plane or to the PICB. This often requires plug-in or receptacle optical connectors that, in some respects, may be similar to plug-in and receptacle electrical connectors used for electrical circuit-board components. Alternatively, the optical interface may be accomplished with a connector end adapted to be permanently (or semi-permanently) fixed to the PICB to establish and maintain optical communication with corresponding devices (e.g., photodetectors or phototransmitters) on the PICB.
Because interior space is typically at a premium for most optical and electrical-optical devices, the optical interface devices and the PICBs are preferably compact so that they can fit into tight spaces. For example, multiple PICBs are often arranged in a stacked configuration within data communications racks, so that the height of the optical interface devices is preferably as small as possible while still being able to carry out their function for transmitting optical signals with suitable optical performance.
Consequently, there is a need for continuing improvements to PICB technology that provide for compact configurations while also providing for high-efficiency optical coupling between the PICB and another device to which it is optically coupled.